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Moran M.C.,University of Coimbra | Miguel M.G.,University of Coimbra | Lindman B.,University of Coimbra | Lindman B.,Center for Chemistry and Chemical Engineering
Soft Matter | Year: 2010

This review covers recent developments on the topic of DNA gel particles formed in water-water emulsion-type interfaces. A general understanding of interactions between DNA and oppositely charged agents has given us a basis for developing novel DNA-based materials, including gel particles. The association strength, which is tuned by varying the chemical structure of the cationic cosolute, determines the spatial homogeneity of the gelation process, creating DNA reservoir devices and DNA matrix devices that can be designed to release DNA (either single- (ssDNA) or double-stranded (dsDNA)). Besides an introduction concerning general aspects about DNA-cationic complexes and the formation of gels in water-water emulsion-type interfaces and some conclusions, the review contains sections reviewing the preparation of DNA gel particles using 1) surfactants, 2) polysaccharides and 3) proteins. The particle morphology, swelling/dissolution behaviour, degree of DNA entrapment and DNA release responses as a function of the nature of the cationic agent used are discussed. Finally, current directions on the preparation of DNA gel particles, including the decrease of size and the improvement of the biocompatibility of these systems have been reviewed. © The Royal Society of Chemistry 2010.

Walderhaug H.,University of Oslo | Soderman O.,Center for Chemistry and Chemical Engineering | Topgaard D.,Center for Chemistry and Chemical Engineering
Progress in Nuclear Magnetic Resonance Spectroscopy | Year: 2010

Pulsed field-gradient spin-echo (PGSE) NMR methods were employed to investigate self-diffusion in polymer systems. These methods were specifically employed to those polymer systems that were grouped under the topic 'soft polymer systems'. The PGSE experiment was performed by recording the NMR signal I as a function of b by varying G at constant values of all timing variables, keeping the relaxation factors constant. The investigations also focused on the particular features that were considered when performing NMR diffusometry experiments on polymer solutions. Polymer systems used in the investigations referred to two-component systems with polymeric molecules dissolved in a low molecular weight solvent. It was demonstrated that most PGSE NMR investigations were performed on polymers in good solvents in such systems.

Bernstad A.,Lund University | La Cour Jansen J.,Center for Chemistry and Chemical Engineering | Aspegren H.,VA SYD
Waste Management and Research | Year: 2011

The environmental impact of an extended property close source-separation system for solid household waste (i.e. a systems for collection of recyclables from domestic properties) is investigated in a residential area in southern Sweden. Since 2001, households have been able to source-separate waste into six fractions of dry recyclables and food waste sorting. The current system was evaluated using the EASEWASTE life cycle assessment tool. Current status is compared with an ideal scenario in which households display perfect source-separation behaviour and a scenario without any material recycling. Results show that current recycling provides substantial environmental benefits compared to a non-recycling alternative. The environmental benefit varies greatly between recyclable fractions, and the recyclables currently most frequently source-separated by households are often not the most beneficial from an environmental perspective. With optimal source-separation of all recyclables, the current net contribution to global warming could be changed to a net-avoidance while current avoidance of nutrient enrichment, acidification and photochemical ozone formation could be doubled. Sensitivity analyses show that thetype of energy substituted by incineration of non-recycled waste, as well as energy used in recycling processes and in the production of materials substituted by waste recycling, is of high relevance for the attained results. © The Author(s) 2011.

Karlstrom G.,Center for Chemistry and Chemical Engineering | Linse P.,Center for Chemistry and Chemical Engineering
Journal of Chemical Physics | Year: 2010

A strongly coupled dipolar fluid confined in a sphere has been examined by Monte Carlo simulations using a modified distance-dependent pair interaction to emulate retardation effects. The effective dipole-dipole interaction and a property closely related to Kirkwood's g-factor have been analyzed for potentials with different distances at which the retardation effects became effective. The retardation effects were found to break the otherwise long-range structural ordering occurring in strongly coupled dipolar fluids. © 2010 American Institute of Physics.

Karlstrom G.,Center for Chemistry and Chemical Engineering | Linse P.,Center for Chemistry and Chemical Engineering | Woodward C.E.,University of Canberra
Journal of Chemical Physics | Year: 2010

General expressions for two-center electrostatic potential correlations and its use to determine (i) the effective interaction between simple ions in a dipolar solvent and (ii) the dielectric permittivity of the solvent are proposed. Such two-center potential correlations were determined from Monte Carlo simulations of spherically confined dipolar particles embedded in a dielectric medium described by using an image charge approximation. The deduced dielectric permittivities increased with increasing dipolar moment, and at large dipole moments the effective interaction displayed an attractive first minimum. © 2010 American Institute of Physics.

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